Shelves, partitions
Dado / housing
A trench across the side so a shelf or divider has a shoulder under the load.
Use when
- A shelf has to carry books or dishes and a screw through the side is not the look you want.
- The housing can show on the front edge, or you will stop it short.
Don’t use when
- Do not use a dado as the only corner joint on a box.
- Do not glue a wide solid shelf into a full-length housing if the case will see real humidity swings.
- Keep
- Waste, hatched on the drawing
- Dimension
- Long parts are broken. The 1 in bar is true scale.
Stock
Thickness steppers move by 1/16 in, or 0.5 mm. You can type 3/4 or 1-1/8.
Sizes
| Mark | Size | Rule |
|---|---|---|
| Dado depth | 3/8 in | Prefer 3/8 in, clamped to 1/3–1/2 of the side |
| Dado width | 3/4 in | Equals shelf thickness. 3/4 in (matches a 3/4 in bit) |
| Side thickness | 3/4 in | Reference member — size the housing from this |
| Shelf thickness | 3/4 in | Sets the housing width |
Cut sequence
1Knife both walls
Stand the shelf on the side and knife the housing. Cross the grain. Carry the marks onto the near edge so the depth has a witness.
Setup: Wall spacing = 3/4 in. Depth mark = 3/8 in.
Stop when: Both knife walls are visible on the face and the edge.
2Saw the walls
Crosscut just on the waste side of each knife line, down to the depth mark. A bench hook keeps the side from skating.
Setup: Saw depth = 3/8 in.
Stop when: The kerf kisses the depth line and does not pass it.
3Chop the waste
Chisel from both faces toward the middle so the far side does not tear out. Finish with the bevel down, riding the depth line.
Setup: Floor at 3/8 in.
Stop when: A straightedge shows a flat floor and both walls are clean.
4Fit the shelf
The shelf should enter with hand pressure. If it is tight, plane the shelf — not the housing — until it sits on the floor without a rock.
Stop when: The shelf seats fully and the face lines up with your knife mark.
5Dry-fit, then glue
Close the joint dry. Check that shoulders and faces meet, then glue. If this is a frame or a box, check both diagonals before the glue grabs.
Stop when: Dry-fit is tight with hand pressure, square, and the diagonals match.
Glue
Long grain to end grain
Strength
furniture
Movement
Hardwood still moves across the grain. A joint that locks that movement with no slot will open or split. The shelf end is end grain against the side face. Glue holds the floor; the walls do the work.
Common mistakes
- Sizing the housing to a bit you own instead of the shelf you planed.
- A floor that is deeper at the back than the front, so the shelf rocks.
- Tear-out where the cutter exits the show edge.
- A stopped housing with no notch in the shelf, so the front sticks out.
- Gluing the full length of a solid shelf, then blaming the wood when the side splits.